The present invention is directed to devices and methods of adjusting the transmission ratio (speed ratio) between a motor output and a transmission output shaft. Various methods of varying the transmission ratio have been described in the past. Many prior art systems use pulleys and/or belts to provide a continuously variable transmission. These systems have inherent mechanical inefficiencies as well as parts, such as belts, which tend to wear and may require one or more replacements during the life of the system.
The present invention is also directed to methods and systems for combining the power of two or more motors. The combination of power may be used to perform any type of work. The present invention may be used in systems which typically have only one motor and, of course, has obvious applications for systems having two motors such as so-called hybrid vehicles. The present invention is particularly advantageous when combining the power of a heat engine, such as an internal combustion engine, with the power of an electrical motor.
The present invention is also directed to methods of controlling the operation of two motors. In particular, the present invention is directed to increased efficiency and/or increased performance.